How to Enable PCIe in imx6Q

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How to Enable PCIe in imx6Q

1,409 次查看
zohanlin
Contributor IV

Dear guys,

My kernel is v4.9.88 and my board is i.MX6Q.

I refer the link in NXP

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/i-MX6Q-PCIe-EP-RC-Validation-System/ta-p...

 

For enabling PCIe function in imx6Q, I have three questions.

1. Do I need to enable CONFIG_RC_MODE_IN_EP_RC_SYS=y if I want plug a EP mode PCIe device to imx6Q?

2. Are the CONFIG_RC_MODE_IN_EP_RC_SYS &  the CONFIG_EP_MODE_IN_EP_RC_SYS only for testing R/W speed between two i.MX boards?

3. Do I need to enable cache for PCIe function in normal case? If yes, how to enable cache for PCIe?

 

Thanks,

zohan

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1,406 次查看
igorpadykov
NXP Employee
NXP Employee

Hi Zohan

 

1. please use option on that link

"Software configurations
* When building RC image"

2. no

3. suggested to use default dts:

https://source.codeaurora.org/external/imx/linux-imx/tree/arch/arm/boot/dts/imx6q-sabresd.dts?h=imx_...

 

Best regards
igor

 

 

 

 

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zohanlin
Contributor IV

Hi igor,

I plugged SIMCOM 5G module(EP mode) to i.MX6Q board, 

the PCIe read speed is 1.8 MB/s,  write speed is 7.8 MB/s.

 

I see the i.MX6Q spec it says the i.MX6Q support PCIe 2.0

Why the speed is slower than PCIe Gen 1?

 

I also done the same test on i.MX6QP EVB without externel OSC.

And the result is almost same as i.MX6Q.

 

Do you have any suggestion about my problem?

 

Thanks,

zohan

 

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igorpadykov
NXP Employee
NXP Employee

bad performance may be due to noisy signals, one can try steps provided in AN4784 and

check if signal quality is good

AN4784: PCIe Certification Guide for i.MX 6Dual/6Quad and i.MX 6Solo/6DualLite - Application Note

 

Best regards
igor

 

 

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zohanlin
Contributor IV

Hi igor,

We don't have those test equipments.

And we have test two 5G modules on i.MX6QP EVB: 

(1)SIMCOM SIM8202G-M2

(2)QUECTEL RM502Q-AE

SIMCOM & QUECTEL both have bad upload & download speed.

Their upload speed is about 2MB/s and download speed is about 6MB/s.

Do you have any idea about the issue?

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